ECSS-E-ST-35-10 belongs to the propulsion field of the mechanical discipline, as defined in ECSS-S-ST-00, and concerns itself with compatibility testing of propulsion components, sub-systems and systems. Compatibility encompasses the interaction of two or more materials, solids (e. g. structural materials), liquids (e. g. propellants, simulation and cleaning liquids) or gases (e. g. air, pressurants). In case the interaction has the effect that the properties of the materials change, there is the possibility of a compatibility issue.The standard: ? identifies materials used in propulsion for which incompatibility can create problems, ? identifies the time scale at which problems can occur. It makes a difference whether a system is only stored or operational for a short period and is to function only during launch (time scale measured in months) and systems that have a long life in orbit (time scale measured in years), ? identifies the liquid propulsion components, subsystems and systems to be subject to compatibility testing, ? identifies, specifies and defines the tests, test conditions and compatibility test procedures to ensure that representative compatibility testing can take place, and ? establishes the test requirements.The standard is applicable to the design and the qualification of liquid propulsion components, sub-systems and systems and can be applied to their development; it also applies to COTS items procured for the propulsion system.From the tests described in this standard the effects of interactions of space propulsion materials and fluids on the components, subsystems and systems can be established. In this way it can be assured that the component, subsystem or system satisfies the requirements.This standard is limited to tests on component-, subsystem- and system-level. Only for those cases where new materials, substances or conditions are involved for which there is no experience or data available, the performance of screening tests is specified.This standard may be tailored for the specific characteristic and constrains of a space project in conformance with ECSS-S-ST-00.